Optical navigation sensors (ONS) are commonly used in devices, such as an optical computer mouse, trackball or touch pad, for interfacing with personal computers and workstations. One technology used for optical navigation sensors relies on light from a coherent source reflected or scattered off of an optically rough surface to generate a complex interference pattern of light known as speckle. The speckle image is mapped to an array of photosensitive elements, such as photodiodes, through an imaging system including a finite, angular field-of-view or numerical aperture. Movement of this image is tracked as it moves back and forth across the array through signal processing and from that tracking the motion of the ONS relative to the surface is derived.